Radio frequency (RF) filters and multiplexers having filters typically employ a plurality of resonators. So that such filters will function as intended and designed, each resonator must be suitably decoupled from its neighbors. This is most frequently accomplished by spacing the resonators at sufficient distances from each other to avoid excessive coupling.
However, in many environments space is at a premium. This requires resonators to be physically positioned closer together than is otherwise desirable. Under such circumstances a variety of techniques have been employed to provide for suitable decoupling. One typical approach has been to insert a dividing wall between adjacent resonators. Another has been to use mechanical irises. Each of these involves substantial expense.
It would be desirable to provide a less expensive, potentially adjustable, possibly more effective decoupling mechanism, especially for metal interdigital and combline filters, i.e., metal filters employing resonators arranged in interdigital and combline arrays, as well as for dielectric block filters.